====================================================== WARNING: possible circular locking dependency detected 6.15.0-syzkaller-08297-ge0797d3b91de #0 Not tainted ------------------------------------------------------ syz.1.636/5538 is trying to acquire lock: ffff80008748ae88 (pcpu_alloc_mutex){+.+.}-{4:4}, at: pcpu_alloc_noprof+0x8ac/0x11e4 mm/percpu.c:1782 but task is already holding lock: ffff0000144febe8 (&q->q_usage_counter(io)#34){++++}-{0:0}, at: blk_mq_freeze_queue_nomemsave block/blk-mq.c:205 [inline] ffff0000144febe8 (&q->q_usage_counter(io)#34){++++}-{0:0}, at: __blk_mq_update_nr_hw_queues block/blk-mq.c:4993 [inline] ffff0000144febe8 (&q->q_usage_counter(io)#34){++++}-{0:0}, at: blk_mq_update_nr_hw_queues+0x1e4/0x8e0 block/blk-mq.c:5043 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (&q->q_usage_counter(io)#34){++++}-{0:0}: blk_alloc_queue+0x534/0x640 block/blk-core.c:461 blk_mq_alloc_queue+0x14c/0x22c block/blk-mq.c:4396 __blk_mq_alloc_disk+0x20/0x1a4 block/blk-mq.c:4443 nbd_dev_add+0x3cc/0x9d0 drivers/block/nbd.c:1933 nbd_init+0xd4/0x1a8 drivers/block/nbd.c:2670 do_one_initcall+0x130/0x7f0 init/main.c:1257 do_initcall_level init/main.c:1319 [inline] do_initcalls init/main.c:1335 [inline] do_basic_setup init/main.c:1354 [inline] kernel_init_freeable+0x488/0x6f0 init/main.c:1567 kernel_init+0x24/0x1e0 init/main.c:1457 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:862 -> #1 (fs_reclaim){+.+.}-{0:0}: __fs_reclaim_acquire mm/page_alloc.c:4056 [inline] fs_reclaim_acquire+0x138/0x160 mm/page_alloc.c:4070 might_alloc include/linux/sched/mm.h:318 [inline] prepare_alloc_pages+0x168/0x560 mm/page_alloc.c:4738 __alloc_frozen_pages_noprof+0x144/0x1f1c mm/page_alloc.c:4959 __alloc_pages_noprof+0x14/0x114 mm/page_alloc.c:5004 __alloc_pages_node_noprof include/linux/gfp.h:284 [inline] alloc_pages_node_noprof include/linux/gfp.h:311 [inline] pcpu_alloc_pages mm/percpu-vm.c:95 [inline] pcpu_populate_chunk+0xf0/0x90c mm/percpu-vm.c:285 pcpu_alloc_noprof+0x688/0x11e4 mm/percpu.c:1870 bpf_map_alloc_percpu+0xe4/0x5ac kernel/bpf/syscall.c:556 bpf_array_alloc_percpu kernel/bpf/arraymap.c:38 [inline] array_map_alloc+0x430/0x57c kernel/bpf/arraymap.c:152 map_create+0x3b8/0x17e0 kernel/bpf/syscall.c:1477 __sys_bpf+0x844/0x25ac kernel/bpf/syscall.c:5818 __do_sys_bpf kernel/bpf/syscall.c:5943 [inline] __se_sys_bpf kernel/bpf/syscall.c:5941 [inline] __arm64_sys_bpf+0x70/0xa4 kernel/bpf/syscall.c:5941 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x6c/0x258 arch/arm64/kernel/syscall.c:49 el0_svc_common.constprop.0+0xac/0x230 arch/arm64/kernel/syscall.c:132 do_el0_svc+0x40/0x58 arch/arm64/kernel/syscall.c:151 el0_svc+0x50/0x198 arch/arm64/kernel/entry-common.c:767 el0t_64_sync_handler+0x10c/0x138 arch/arm64/kernel/entry-common.c:786 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:600 -> #0 (pcpu_alloc_mutex){+.+.}-{4:4}: check_prev_add kernel/locking/lockdep.c:3168 [inline] check_prevs_add kernel/locking/lockdep.c:3287 [inline] validate_chain kernel/locking/lockdep.c:3911 [inline] __lock_acquire+0x1638/0x2380 kernel/locking/lockdep.c:5240 lock_acquire kernel/locking/lockdep.c:5871 [inline] lock_acquire+0x310/0x38c kernel/locking/lockdep.c:5828 __mutex_lock_common kernel/locking/mutex.c:601 [inline] __mutex_lock+0x144/0x9d8 kernel/locking/mutex.c:746 mutex_lock_killable_nested+0x24/0x30 kernel/locking/mutex.c:813 pcpu_alloc_noprof+0x8ac/0x11e4 mm/percpu.c:1782 init_alloc_hint lib/sbitmap.c:16 [inline] sbitmap_init_node+0x220/0x714 lib/sbitmap.c:126 sbitmap_queue_init_node+0x3c/0x584 lib/sbitmap.c:438 bt_alloc block/blk-mq-tag.c:542 [inline] blk_mq_init_tags+0x100/0x230 block/blk-mq-tag.c:565 blk_mq_alloc_rq_map block/blk-mq.c:3538 [inline] blk_mq_alloc_map_and_rqs+0xa4/0xc54 block/blk-mq.c:4094 __blk_mq_alloc_map_and_rqs block/blk-mq.c:4116 [inline] __blk_mq_alloc_map_and_rqs+0x100/0x1dc block/blk-mq.c:4107 blk_mq_realloc_tag_set_tags block/blk-mq.c:4755 [inline] __blk_mq_update_nr_hw_queues block/blk-mq.c:4995 [inline] blk_mq_update_nr_hw_queues+0x344/0x8e0 block/blk-mq.c:5043 nbd_start_device+0xf8/0x9d0 drivers/block/nbd.c:1476 nbd_start_device_ioctl drivers/block/nbd.c:1527 [inline] __nbd_ioctl drivers/block/nbd.c:1602 [inline] nbd_ioctl+0x178/0xa08 drivers/block/nbd.c:1642 blkdev_ioctl+0x22c/0x7f4 block/ioctl.c:704 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:907 [inline] __se_sys_ioctl fs/ioctl.c:893 [inline] __arm64_sys_ioctl+0x124/0x1a4 fs/ioctl.c:893 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x6c/0x258 arch/arm64/kernel/syscall.c:49 el0_svc_common.constprop.0+0xac/0x230 arch/arm64/kernel/syscall.c:132 do_el0_svc+0x40/0x58 arch/arm64/kernel/syscall.c:151 el0_svc+0x50/0x198 arch/arm64/kernel/entry-common.c:767 el0t_64_sync_handler+0x10c/0x138 arch/arm64/kernel/entry-common.c:786 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:600 other info that might help us debug this: Chain exists of: pcpu_alloc_mutex --> fs_reclaim --> &q->q_usage_counter(io)#34 Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&q->q_usage_counter(io)#34); lock(fs_reclaim); lock(&q->q_usage_counter(io)#34); lock(pcpu_alloc_mutex); *** DEADLOCK *** 5 locks held by syz.1.636/5538: #0: ffff0000148b9a30 (&nbd->config_lock){+.+.}-{4:4}, at: nbd_ioctl+0x100/0xa08 drivers/block/nbd.c:1635 #1: ffff0000148b9988 (&set->update_nr_hwq_lock){++++}-{4:4}, at: blk_mq_update_nr_hw_queues+0x44/0x8e0 block/blk-mq.c:5041 #2: ffff0000148b98d8 (&set->tag_list_lock){+.+.}-{4:4}, at: blk_mq_update_nr_hw_queues+0x50/0x8e0 block/blk-mq.c:5042 #3: ffff0000144febe8 (&q->q_usage_counter(io)#34){++++}-{0:0}, at: blk_mq_freeze_queue_nomemsave block/blk-mq.c:205 [inline] #3: ffff0000144febe8 (&q->q_usage_counter(io)#34){++++}-{0:0}, at: __blk_mq_update_nr_hw_queues block/blk-mq.c:4993 [inline] #3: ffff0000144febe8 (&q->q_usage_counter(io)#34){++++}-{0:0}, at: blk_mq_update_nr_hw_queues+0x1e4/0x8e0 block/blk-mq.c:5043 #4: ffff0000144fec20 (&q->q_usage_counter(queue)#2){+.+.}-{0:0}, at: blk_mq_freeze_queue_nomemsave block/blk-mq.c:205 [inline] #4: ffff0000144fec20 (&q->q_usage_counter(queue)#2){+.+.}-{0:0}, at: __blk_mq_update_nr_hw_queues block/blk-mq.c:4993 [inline] #4: ffff0000144fec20 (&q->q_usage_counter(queue)#2){+.+.}-{0:0}, at: blk_mq_update_nr_hw_queues+0x1e4/0x8e0 block/blk-mq.c:5043 stack backtrace: CPU: 1 UID: 0 PID: 5538 Comm: syz.1.636 Not tainted 6.15.0-syzkaller-08297-ge0797d3b91de #0 PREEMPT Hardware name: linux,dummy-virt (DT) Call trace: show_stack+0x18/0x24 arch/arm64/kernel/stacktrace.c:466 (C) __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0xa4/0xf4 lib/dump_stack.c:120 dump_stack+0x1c/0x28 lib/dump_stack.c:129 print_circular_bug+0x28c/0x370 kernel/locking/lockdep.c:2046 check_noncircular+0x168/0x17c kernel/locking/lockdep.c:2178 check_prev_add kernel/locking/lockdep.c:3168 [inline] check_prevs_add kernel/locking/lockdep.c:3287 [inline] validate_chain kernel/locking/lockdep.c:3911 [inline] __lock_acquire+0x1638/0x2380 kernel/locking/lockdep.c:5240 lock_acquire kernel/locking/lockdep.c:5871 [inline] lock_acquire+0x310/0x38c kernel/locking/lockdep.c:5828 __mutex_lock_common kernel/locking/mutex.c:601 [inline] __mutex_lock+0x144/0x9d8 kernel/locking/mutex.c:746 mutex_lock_killable_nested+0x24/0x30 kernel/locking/mutex.c:813 pcpu_alloc_noprof+0x8ac/0x11e4 mm/percpu.c:1782 init_alloc_hint lib/sbitmap.c:16 [inline] sbitmap_init_node+0x220/0x714 lib/sbitmap.c:126 sbitmap_queue_init_node+0x3c/0x584 lib/sbitmap.c:438 bt_alloc block/blk-mq-tag.c:542 [inline] blk_mq_init_tags+0x100/0x230 block/blk-mq-tag.c:565 blk_mq_alloc_rq_map block/blk-mq.c:3538 [inline] blk_mq_alloc_map_and_rqs+0xa4/0xc54 block/blk-mq.c:4094 __blk_mq_alloc_map_and_rqs block/blk-mq.c:4116 [inline] __blk_mq_alloc_map_and_rqs+0x100/0x1dc block/blk-mq.c:4107 blk_mq_realloc_tag_set_tags block/blk-mq.c:4755 [inline] __blk_mq_update_nr_hw_queues block/blk-mq.c:4995 [inline] blk_mq_update_nr_hw_queues+0x344/0x8e0 block/blk-mq.c:5043 nbd_start_device+0xf8/0x9d0 drivers/block/nbd.c:1476 nbd_start_device_ioctl drivers/block/nbd.c:1527 [inline] __nbd_ioctl drivers/block/nbd.c:1602 [inline] nbd_ioctl+0x178/0xa08 drivers/block/nbd.c:1642 blkdev_ioctl+0x22c/0x7f4 block/ioctl.c:704 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:907 [inline] __se_sys_ioctl fs/ioctl.c:893 [inline] __arm64_sys_ioctl+0x124/0x1a4 fs/ioctl.c:893 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x6c/0x258 arch/arm64/kernel/syscall.c:49 el0_svc_common.constprop.0+0xac/0x230 arch/arm64/kernel/syscall.c:132 do_el0_svc+0x40/0x58 arch/arm64/kernel/syscall.c:151 el0_svc+0x50/0x198 arch/arm64/kernel/entry-common.c:767 el0t_64_sync_handler+0x10c/0x138 arch/arm64/kernel/entry-common.c:786 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:600 block nbd1: shutting down sockets